<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Responsive Image</title>
    <style>
        body {
            margin: 0;
            padding: 0;
        }

        .container {
            height: 800px;
            margin: 50px auto;
            text-align: center;
            font-size: 0;
            background-color: aqua;
        }

        img {
            max-width: 100%;
            height: auto;
        }
    </style>
</head>

<body>
    <div class="container">
        <picture>
            <source srcset="./img/魅族.png" media="(max-width: 400px)">
            <source srcset="./img/魅族big.png" media="(max-width: 800px)">
            <img src="./img/魅族bigger.png" alt="Responsive Image">
        </picture>
    </div>
</body>

</html>